Sorry for the delay in the reply, haven't been able to access the internet properly for a little while...
Try moving your iphoto library to a different location (desktop as an example), to do this go to Home (Your Username in the finder window) > Pictures and move the file called iPhoto Library.
Re-open iphoto to see if that solves the problem and iPhoto opens correctly. If it does, close iPhoto move your library back and reopen iPhoto again using the same procedure I mentioned above, if it does not work then maybe a re-installation of iLife is needed :s

HTH,

- Simon

If you have been helped, don't forget to use the Reputation system at the top right of their post. May 2011
Nominated: March 2011 & April 2011

Tried everything apart fro re-installing..it all seems connected in some way. I've been deleting plists and re-booting to no avail and am beginning to think a complete clean slate is required regarding backing up data and reinstalling OSX and starting from scratch.